Python is a powerful and versatile programming language. Writing clean, efficient, and maintainable Python code is crucial for productivity and collaboration. Here are the best practices for Python development, covering everything from code structure to performance optimization.
1. Follow PEP 8 – The Python Style Guide
Consistent indentation – Use 4 spaces per indentation level
Limit line length – Keep lines ≤ 79 characters (72 for docstrings)
Use meaningful variable names – Avoid single-letter names except for loop counters
Write readable function names – Use snake_case for functions and variables
Class names should be in PascalCase
Use spaces around operators
Use docstrings for functions and classes
Example:
def calculate_area(width: float, height: float) -> float:
"""Calculate the area of a rectangle."""
return width * height
2. Use Virtual Environments
A virtual environment isolates project dependencies, preventing conflicts between different projects.
Use venv for creating isolated environments
python -m venv myenv
source myenv/bin/activate # On Windows: myenv\Scripts\activate
Use pip freeze to save dependencies
pip freeze > requirements.txt
Install dependencies from a file
pip install -r requirements.txt
3. Write Clean and Modular Code
Follow the DRY Principle – Don’t Repeat Yourself
Break large functions into smaller reusable functions
Use classes to group related functions
Example:
class Rectangle:
def __init__(self, width: float, height: float):
self.width = width
self.height = height
def area(self) -> float:
return self.width * self.height
4. Use List Comprehensions and Generators
List comprehensions make loops cleaner and faster
Generators save memory by yielding values instead of storing them
Example (List Comprehension):
squares = [x**2 for x in range(10) if x % 2 == 0]
Example (Generator Function):
def even_numbers(n):
for i in range(n):
if i % 2 == 0:
yield i
evens = even_numbers(10)
print(list(evens)) # Output: [0, 2, 4, 6, 8]
5. Handle Exceptions Properly
Always handle errors to prevent crashes
Use specific exception types instead of except Exception:
Example:
try:
num = int(input("Enter a number: "))
result = 10 / num
except ValueError:
print("Invalid input! Please enter a number.")
except ZeroDivisionError:
print("Cannot divide by zero!")
except Exception as e:
print(f"Unexpected error: {e}")
finally:
print("Execution complete.")
6. Use Type Hinting
Improve readability and prevent type-related bugs
Example:
def add_numbers(a: int, b: int) -> int:
return a + b
7. Use f-strings for String Formatting
Faster and more readable than format() and % formatting
name = "Alice"
age = 25
print(f"Hello, my name is {name} and I am {age} years old.")
8. Optimize Performance
Use built-in functions (e.g., sum(), map(), filter())
Avoid using unnecessary loops
Use set() for fast membership testing
Use multiprocessing for parallel execution
Example (Using map instead of a loop):
numbers = [1, 2, 3, 4, 5]
squared = list(map(lambda x: x**2, numbers)) # Faster than a for loop
9. Use Logging Instead of Print Statements
Print statements are not suitable for production debugging
Use Python’s built-in logging module
Example:
import logging
logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")
logging.info("This is an informational message.")
10. Follow Good Documentation Practices
Use docstrings for functions and classes
Maintain a README file for projects
Use tools like Sphinx or MkDocs for auto-generating documentation
Example:
def greet(name: str) -> str:
"""Returns a greeting message for the given name."""
return f"Hello, {name}!"
11. Use Efficient Data Structures
Prefer dict and set over list for lookups
Use collections.deque for fast FIFO operations
Example (Using set for fast lookups):
nums = {1, 2, 3, 4, 5} # O(1) lookup time
print(3 in nums) # True
12. Follow Secure Coding Practices
Avoid hardcoding credentials
Use .env files for secrets
Sanitize user inputs to prevent injection attacks
Use parameterized queries in SQL
Example (Using .env files with dotenv):
from dotenv import load_dotenv
import os
load_dotenv()
db_password = os.getenv("DB_PASSWORD")
13. Write Unit Tests
Use unittest or pytest to write test cases
Run tests before deployment
Example (Using unittest):
import unittest
def add(a, b):
return a + b
class TestMath(unittest.TestCase):
def test_add(self):
self.assertEqual(add(2, 3), 5)
if __name__ == "__main__":
unittest.main()
14. Automate Tasks with CI/CD
Use GitHub Actions, Jenkins, or GitLab CI/CD
Automate testing, linting, and deployments
15. Follow Best Git Practices
Write clear commit messages
Use branches for features (feature-branch)
Use .gitignore to exclude unnecessary files